Radiation enhanced reactivity of UO2

Pure UO2 is often used as a model compound when studying reactions of importance in a future deep repository for spent nuclear fuel. The reactivity of pure UO2 is not expected to be identical to the reactivity of the UO2-matrix of spent nuclear fuel for several reasons. One reason is that the spent fuel, due to the content of radionuclides, is continuously being self-irradiated. The aim of this study is to investigate how irradiation of solid UO2 surfaces affects their reactivity towards oxidants. The effect of irradiation (γ or electrons) on the reaction between solid UO2 and MnO 4 - in aqueous solutions containing carbonate has been studied. It was found that irradiation with high doses (>40 kGy) increased the reactivity of the UO2 to about 1.3 times the reactivity of unirradiated UO2.